"I don't like old people on a rock 'n' roll stage. What you're pretty much doing is imitating yourself at the age of 25, and there's basically nothing more pathetic." -- Grace Slick

Finally found people even touchier than Islamic fanatics: Led Zeppelin fanatics.

No kidding. I say this after receiving a pretty heavy mailbag on my recent column about the Zep reunion concert in London. It was the "worst" column, a work of "concentrated stupidity," I must have been "stoned" to have written it, my work should be "boycotted." ("Carry your (boycott West) signs on to the streets, hang them in windows and pin them up in your work place cubicle," commented one free-speech enthusiast at the conservative Web site townhall.com.)

You see, I had dared to go for a few laughs at the expense of aging (aged) rockers and their aging (aged) fans, most of whom believe you're just not living if you're not 14, or acting like it. And not only is my anti-establishment, alternative point of view verboten, there is also nothing funny about the aging (aged) concert scene, what with Led Zeppelin settling into its set, as one account reported, as "grown men in the mostly middle-aged and male audience began playing air guitar."

Nothing funny, that is, if you happen to be a middle-aged male who plays air guitar. I heard from several such air musicians, including the one who reminded me that "the Founding Fathers fought for our freedom to play air guitar at 50."

So no jokes.

That said, there remains the more serious punch line pertaining to the phenomenon I like to call "the death of the grown-up." In fact, as some readers know, I have even written a book by the same title devoted to exploring how and why we came to a place in the progression of the species where, quite suddenly, adolescence is no longer a phase to pass through, but, in many ways, the endpoint -- the culmination -- of our emotional and aesthetic development (and why this threatens our liberty).

A "heritage rock event" such as Led Zeppelin's onstage reunion is a good place to assess the phenomenon. Here, the erstwhile don't-trust-anyone-over-30 set gathers to retool its creed for its Golden Years: Don't trust anyone who acts over 30 -- or worse, imagines there is something amiss in the pretense. Continued...